The proposed research project will use quantitative and qualitative data to explore features of the social and situational contexts in which young (18-30 yrs old) Black men who have sex with men (BMSM) meet other men and engage in sexual behaviors. The research will focus on understanding the contextual factors associated with risk behavior. Contextual factors are conceptualized in two ways: 1) those proximally linked to sexual risk-taking (i.e., proximal risk factors, such as substance use during sexual activity, characteristics of sex partners and settings, feelings toward sex partners, and communication with sex partners), and 2) those distally related to sexual risk-taking (i.e., distal risk factors, such as childhood and adolescent exposure to abject poverty, substance use by parents or caregivers, and/or violence and trauma). The research will also explore resiliency and other personal and social factors associated with HIV protective behaviors among young BMSM, as well as describe the barriers and facilitators to effective HIV prevention and treatment in this population. The overarching goal of the work is to aid in the identification of potentially effective components of prevention messages and individual-, group-, and community-level interventions directed toward young BMSM. Qualitative data will be derived from life history interviews conducted with 50 young Black MSM. Quantitative data will be collected through a cross-sectional survey and a longitudinal, Internet-based structured weekly diary that 200 young BMSM will complete. The proposed study has great significance to public health, by examining the factors that that may place young BMSM at heightened risk for HIV. Few large-scale research projects have been conducted with this group, and only a small number of interventions have been designed that effectively reach this population. The project takes a conceptual and analytical approach that focuses on describing the contexts of sexual risk-taking behavior among young BMSM. By taking this approach, we are better able to ascertain effective prevention messages, and to identify the necessary components of individual-, group-, and community-level interventions directed toward young BMSM.